Asynchronous function decorator, within a class.

[mplatypus]

The title might be a bit confusing, but I do have two kinds of questions here (feel free to let me know if they should be separate)

Basically, my first question is, how can I make an async function decorator, and type it appropriately?

@some_decorator()
async def some_function() -> None:
    pass

Then, the second question is, how can I then take that (or just do the following)

some_parent = SomeParent()

@some_parent.some_decorator()
async def some_function() -> None:
    pass

(Would also be curious for that second half, what that would look like in terms of a non-async version.)

[davidhewitt]

I assume you mean something like https://pyo3.rs/v0.25.1/class/call.html?highlight=decorato#example-implementing-a-call-counter?

The only difference really is that calling an async function will produce an awaitable object, depending on what your decorator does you may need to await it (you can potentially do that yourself, we're also experimenting in #3611 to make some of this built in to PyO3).

[mplatypus]

Pretty much exactly that.

We are currently using pyo3-async-runtimes as our async support with tokio, which seems to run fine for the most part (some hiccups, but it seems most of our issues have been fixed)

We currently have setup a system that works with taking a type and a function (async) into it and parsing it, but were wondering how easy it would be to have support an actual decorator.

This is sort of what the current code looks like.

async def callback(event: Event) -> None:
    print("callback triggered")

parent.subscribe(Event, callback=callback)

but we are hoping for something like this as well:

@parent.listen()
async def callback(event: Event) -> None:
    print("callback triggered")

Which extracts the type of the function and stores the callback, which in itself, would most like just call .subscribe(...) internally, but would also need to do some logic on getting the event parameters type, but that shouldn't be hard, its more the actual signature type of the rust listen function. I'll have a mess around with it soon to see if I can get it to work.

Thank for the reply aswell!